INSECT ENEMIES OF WESTERN FORESTS 187 



lorum Hopk. works in the dead wood of ponderosa pine, Jeffrey 

 pine, and Coulter pine in California, Oregon, and South Dakota. 

 Xyleborus arbuti Hopk. works in madrone, maple, and alder in 

 California and Oregon. Xyleborinus saxeseni (Ratz.) attacks a 

 large variety of hardwoods and is widely distributed in both East- 

 ern and Western States. The galleries consist of simple branching 

 tunnels in which the larvae live and feed upon ambrosial fungus 

 without constructing an enlarged cavity or larval cradles. Xyle- 

 borinus librocedri Sw. attacks the wood of California incense 

 cedar in Oregon, and Xyleborinus tsugae Sw. works in the wood 

 of western hemlock. 



FLATHEADED WOOD BORERS 



The flatheaded borers (Buprestidae) have been previously dis- 

 cussed under the section on cambium or inner-bark miners (p. 

 169). By far the larger number of species, however, are of more 

 economic importance as wood borers than as killers of living trees. 

 Many species work first in the inner bark of dying trees, then 

 extend their tunnels into the sapwood, and even into the heart- 

 wood. The flattened oval wormholes made by the horseshoe-nail- 

 shaped grubs are usually tightly packed with boring dust and may 

 wind in a tortuous fashion back and forth through the wood so as 

 to riddle it completely. Even a few such wormholes greatly lower 

 the quality of the lumber, and a large number make it unfit for 

 any but the roughest use. Some of these wood borers attack the 

 pitchy fire scars on living trees and gradually extend their mines 

 into the sounder portions. Many others attack trees that have 

 been killed or felled and do most of their damage while the wood 

 is still unseasoned. Others will attack wood after it has been run 

 through the mill and is placed in storage, or even after it has been 

 put into use. 



The prevention of fire scars and other injuries to standing trees 

 and the prompt utilization of dead or felled trees will reduce this 

 damage to a low point. In wood that has become infested after 

 being put into place, the grubs usually can be reached and killed by 

 liberal applications of crude orthodichlorobenzene or kerosene. 



The sculptured pine borer (Chalcophora angulicollis Lee.) (fig. 

 86) is the largest of the western species of flatheaded borers and 



Figure 86. — The sculptured pine borer (Chalcophora angulicollis). Natural 



size, 



